The present invention relates to specific photochromic phenanthropyrans, as well as to their use in synthetic resin materials of all types, especially for ophthalmic purposes. In particular, the present invention relates to photochromic compounds, which are derived from 2H-phenanthro[2,1-b]pyrans and 3H-phenanthro[3,4-b]pyrans, which, in the open form, have particularly long-wave absorption maxima, but are still colorless in the unexcited state.
Different classes of dyes are known, which, when irradiated with light of particular wavelengths, especially sunlight, change their color reversibly. This comes about because of the fact that, due to the supply of energy in the form of light, these dye molecules transition into an excited, colored state, which they leave once again when the supply of energy is interrupted, as a result of which they return to their colorless or hardly colored normal state. These photochromic dyes include, for example, the naphthopyrans, which have already been described in the state of the art with different substituents.
Pyrans, especially naphthopyrans and larger ring systems derived from naphthopyrans, are photochromic compounds, which have been the subject of intensive investigations up to the present time. Although the first patents were applied for as early as 1966 (U.S. Pat. No. 3,567,605), compounds, which appeared to be suitable for use in lenses for eyeglasses, were developed only in the 1990s.
The dyes, known from the prior art, frequently have inadequate long-wave absorption in the excited as well as in the unexcited state. This leads to problems even when such dyes are combined with other photochromic dyes. Furthermore, such dyes frequently also exhibit an excessively high temperature sensitivity with respect to the darkening and, at the same time, the lightening or fade is too slow. Moreover, the durability of the dyes available in the prior art frequently is insufficient. Consequently, the durability of such lenses for sunglasses is inadequate. This becomes noticeable due the rapidly decreasing performance and/or the strong yellowing which occurs.
3H-Naphthopyrans, derived from 2-naphthols, and their higher analog derivatives derived by annellation constitute a group of photochromic dyes, the longest wavelength absorption maximum of the excited form of which lies predominantly in the spectral range from 420 nm to 500 nm and accordingly cause a yellow, orange or red-orange color sensation (see U.S. Pat. Nos. 5,869,658 and 6,022,495). However, high-performance, violet to blue photochromic dyes are required for neutral, darkening phototropic glasses. Violet to blue photochromic dyes which are currently available in the art, usually originate from the class of spiroxazine dyes, fulgide dyes or 2H-naphtho[1,2-b]pyrans. Usually, however, spiroxazine dyes are disadvantageous with respect to their high-temperature performance, and fulgide dyes and 2H-naphtho[1,2-b]pyrans have properties which are not completely satisfactory for use in lenses for sunglasses, the former because of the durability and the latter because of the lightening rate.
The introduction of electron-displacing substituents on the aryl groups in the ortho position to the pyran oxygen, as described, for example, in WO 98/45281, WO 01/12619 and EP 0 945 451 A1 leads to red or red violet darkening 3H-naphtho[2,1-b]pyrans. WO 01/12619 discloses compounds in which one geminal aryl group has a para-amino-substituted group and the other aryl group has an alkoxy group or a thioalkoxy group, substituted in the meta or para position, this substitution pattern having a positive effect on the lightening rate. WO 98/45281 describes red hyperchromic compounds which additionally contain an amine function predominantly in the 6-position of the 3H-naphtho[2,1-b]pyran unit. Compounds, with amino groups which do not have pronounced basic properties are described in EP 0 945 451 A1. In the excited state, these compounds show a pink to violet color and have an attractive durability. 3H-Naphtho[2,1-b]pyrans with an aryl substituent in the 6-position are furthermore described in WO 99/31082. The effect of the aryl substitution in the 6-position on the longest wavelength absorption maximum of the unexcited as well as the excited form is, however, very slight in these compounds.
Appropriate substitution in the 8-position of the 3H-naphtho[2,1-b]pyran unit brings about a bathochromic shift in the longest wavelength absorption maximum, especially due to the introduction of alkoxy groups, as described in U.S. Pat. No. 5,238,981. In addition, compounds with dialkylamino groups in the 8-position are also disclosed. The use of nitrogen heterocyclic groups as substituents in the 8-position of the 3H-naphtho[2,1-b]pyran unit is mentioned in U.S. Pat. No. 5,990,305, as a result of which, in contrast to open-chain amino groups, an improved durability is obtained. This is also achieved with substituents which contain so-called HALS (hindered amine light stabilizer) structural units. Finally, violet to blue 3H-naphthol[2,1-b]pyrans, which have substituents containing amino groups in the 3-position as well as in the 8-position, are described in WO 03/055872, and blue 3H-naphthol[2,1-b]pyrans which contain a substituent in the 6-position in addition to the above substituents in the 3 and 8-positions are described in WO 03/080595.
Larger aromatic ring systems, which contain a naphthopyran unit, are described, for example, in U.S. Pat. Nos. 5,106,998, 5,888,432, 4,826,977 and 5,637,709. However, the compounds are not substituted with two aryl groups in the 3-position and instead have at least one saturated polycyclic substituent and thus lead to yellow to red photochromic compounds in the excited form.
Furthermore, U.S. Pat. Nos. 5,565,147, 5,674,432 and 6,294,112 (WO 98/45281) disclose photochromic 3H-naphtho[2,1-b]pyrans which have an annellated heterocyclic unit at the different sides of the naphthalene unit. Accordingly, red hyperchromic 3H-naphtho[2,1-b]pyrans, which may be annellated heterocyclically, are described in U.S. Pat. No. 6,294,112 (WO 98/45281). EP 1 038 870 A1 describes 3H-naphtho[2,1-b]pyrans which have an optionally substituted amido group in the 5-position and the naphthopyran unit of which may be expanded by a heterocyclic or aromatic ring.
Substituted phenanthropyrans are described in U.S. Pat. Nos. 5,514,817 and 6,210,608. These are derived, however, from 2H-naphtho[1,2-b]pyrans.